A valve assembly is often used in a fuel tank to control vapor pressure within the fuel tank. The valve assembly is usually mounted to the fuel tank. Sometimes the fuel tank is formed in two portions, and the valve assembly is mounted to one of the portions so that it can be visibly inspected to ensure that it is properly mounted before the two portions are heat welded or otherwise joined to one another to enclose the valve assembly within the tank. In other configurations, the valve assembly mounts to the tank at an opening. When the valve assembly is visibly mounted at the opening, its proper orientation may be assured by visual inspection.